Underwater mountain range from the southern tier of the Japan Trench to the Hawaiian Islands
The Mid-Pacific Mountains (MPM) is a large
oceanic plateau located in the central North Pacific Ocean or south of the
Hawaiian–Emperor seamount chain. Of volcanic origin and Mesozoic in age, it is located on the oldest part of the
Pacific Plate and rises up to 2 km (1.2 mi) (
Darwin Rise) above the surrounding ocean floor and is covered with several layers of thick sedimentary sequences that differ from those of other plateaux in the North Pacific.[1] About 50 seamounts are distributed over the MPM.[2] Some of the highest points in the range are above sea level which include
Wake Island and
Marcus Island.
The MPM is a range of
guyots with a lava composition similar to those found in Iceland and the Galapagos Islands, and they probably formed similarly at or near a rift system.[4]
In the Cretaceous, they formed large tropical islands located closer to the Equator that began to sink in the late Mesozoic.[5]
The MPM formed in the Early Cretaceous (at
c. 110 Ma) over a
hotspot that uplifted the ocean floor of the still young Pacific Plate. Reefs developed on the subsiding islands and renewed volcanism in the Late Cretaceous helped maintain some of eastern islands but inevitably the guyots sank to their present depth.[6]
It has been proposed that the MPM has crossed over several hotspots, and the MPM guyots are indeed older on the western MPM than the eastern part, but the guyots do not form chains that can be traced to any known hotspots. The MPM, nevertheless, must have originated over the South Pacific
Superswell. Among the guyots in the Mid-Pacific Mountains are
Allison Guyot,
Horizon Guyot,
Resolution Guyot[7] and
Darwin Guyot.[8]
The western half of the
Easter hotspot chain, a lineament that includes the
Line Islands and
Tuamotu archipelago, begins near the eastern part of the MPM.[9] The formation of the MPM thus probably occurred at the
Pacific-Farallon Ridge and the Easter hotspot, or where the
Easter Microplate is now located.
Sources
Citations
^Thiede et al. 1981, Morphology, Age, Plate-Tectonic Setting, and Previous Studies, pp. 1073–1074
Hamilton, E. L. (1956).
"Sunken Islands of the Mid-Pacific Mountains". 64 : Sunken Islands of the Mid-Pacific Mountains. Geological Society of America Memoirs. Vol. 64. Geological Society of America. pp. 1–92.
doi:
10.1130/MEM64-p1. Retrieved 26 October 2017.
Karig, D. E.; Peterson, M. N. A.; Short, G. G. (1970). "Sediment-capped guyots in the Mid-Pacific Mountains". Deep Sea Research and Oceanographic Abstracts. 17 (2): 373–378.
Bibcode:
1970DSRA...17..373K.
doi:
10.1016/0011-7471(70)90029-X.
Wilde, P. (2010). "Supervolcanoes in the Mid-Pacific Mountains?". AGU Fall Meeting Abstracts. 13: V13C–2368.
Bibcode:
2010AGUFM.V13C2368W.
Winterer, E. L.; Metzler, C. V. (1984). "Origin and subsidence of guyots in Mid‐Pacific Mountains". Journal of Geophysical Research: Solid Earth. 89 (B12): 9969–9979.
Bibcode:
1984JGR....89.9969W.
doi:
10.1029/JB089iB12p09969.